Technical Field
The present disclosure relates to a liquid crystal display device (LCD), and particularly, relates to an LCD which can reduce a limitation on a pitch of light emitting diode (LED) packages mounted on a printed circuit board (PCB).
Description of the Related Art
As our society continues to becomes more information-based, the need for various types of display devices continues to increase. Recently, flat display devices, such as a liquid crystal display device (LCD), a plasma display panel device (PDP), and an organic light emitting diode (OLED) display device, have been used by consumers.
Among these display devices, LCDs are widely used because they have desirable properties such as being lightweight, having a thin profile, having a low power consumption, and the like.
A recently employed light source for the LCD is a light emitting diode (LED).
FIG. 1 is a schematic view illustrating an LED assembly for an LED according to the prior art.
Referring to FIG. 1, the LED assembly 20 includes a printed circuit board (PCB) 22 and LED packages 21 spaced apart from each other and mounted on the PCB 22.
The LED package 21 is usually mounted on the PCB 21 using a surface mounting technology (SMT). A surface of the PCB 21 is covered by a coverlay film made of an insulating material, and the coverlay film is formed to expose an electrode pad, of the PCB 22, contacting the LED package 21.
However, in manufacturing the prior art LED assembly 20, due to manufacturing tolerances or the like, there is a limitation that a separation distance d between the LED packages 21 cannot be reduced to less than a certain distance. Accordingly, there is a limitation on a pitch that is an arrangement interval of the LED packages 21.
For example, a mounting tolerance in the SMT is about 100 um with respect to one side of each LED package 21, and an attaching tolerance of the coverlay film is about 100 um with respect to one side of each LED package 21. Further, an insulation width, which is a width of a portion of the coverlay film located between the neighboring LED packages 21, is required to be about 200 um. Accordingly, the separation distance d is required to be at least 600 um that is [(mounting tolerance*2)+(attaching tolerance*2)+insulating width]=[100 um*2+100 un*2+200 um].
As such, the prior art requires the separation distance d of 600 um or greater, and thus a limitation on a pitch of the LED packages 21 happens.
Accordingly, there is a limitation on a number of the LED packages 21 mounted on the PCB 22. Therefore, an optical distance, which is a distance from a light entering surface of a light guide plate to a display region, cannot be reduced, and a realization of a narrow bezel is very difficult to achieve.
As such, there is a continuing need in the art for a method of mounting LCD components that does not have these limitations.